/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cfft_q31.c
*
* Description:	Combined Radix Decimation in Frequency CFFT fixed point processing function
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* -------------------------------------------------------------------- */

#include "arm_math.h"

extern void arm_radix4_butterfly_q31(
    q31_t *pSrc,
    uint32_t fftLen,
    q31_t *pCoef,
    uint32_t twidCoefModifier);

extern void arm_radix4_butterfly_inverse_q31(
    q31_t *pSrc,
    uint32_t fftLen,
    q31_t *pCoef,
    uint32_t twidCoefModifier);

extern void arm_bitreversal_32(
    uint32_t *pSrc,
    const uint16_t bitRevLen,
    const uint16_t *pBitRevTable);

void arm_cfft_radix4by2_q31(
    q31_t *pSrc,
    uint32_t fftLen,
    const q31_t *pCoef);

void arm_cfft_radix4by2_inverse_q31(
    q31_t *pSrc,
    uint32_t fftLen,
    const q31_t *pCoef);

/**
* @ingroup groupTransforms
*/

/**
* @addtogroup ComplexFFT
* @{
*/

/**
* @details
* @brief       Processing function for the fixed-point complex FFT in Q31 format.
* @param[in]      *S    points to an instance of the fixed-point CFFT structure.
* @param[in, out] *p1   points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.
* @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
* @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
* @return none.
*/

void arm_cfft_q31(
    const arm_cfft_instance_q31 *S,
    q31_t *p1,
    uint8_t ifftFlag,
    uint8_t bitReverseFlag)
{
    uint32_t L = S->fftLen;

    if(ifftFlag == 1u)
    {
        switch (L)
        {
        case 16:
        case 64:
        case 256:
        case 1024:
        case 4096:
            arm_radix4_butterfly_inverse_q31  ( p1, L, (q31_t *)S->pTwiddle, 1 );
            break;

        case 32:
        case 128:
        case 512:
        case 2048:
            arm_cfft_radix4by2_inverse_q31  ( p1, L, S->pTwiddle );
            break;
        }
    }
    else
    {
        switch (L)
        {
        case 16:
        case 64:
        case 256:
        case 1024:
        case 4096:
            arm_radix4_butterfly_q31  ( p1, L, (q31_t *)S->pTwiddle, 1 );
            break;

        case 32:
        case 128:
        case 512:
        case 2048:
            arm_cfft_radix4by2_q31  ( p1, L, S->pTwiddle );
            break;
        }
    }

    if( bitReverseFlag )
        arm_bitreversal_32((uint32_t *)p1, S->bitRevLength, S->pBitRevTable);
}

/**
* @} end of ComplexFFT group
*/

void arm_cfft_radix4by2_q31(
    q31_t *pSrc,
    uint32_t fftLen,
    const q31_t *pCoef)
{
    uint32_t i, l;
    uint32_t n2, ia;
    q31_t xt, yt, cosVal, sinVal;
    q31_t p0, p1;

    n2 = fftLen >> 1;
    ia = 0;
    for (i = 0; i < n2; i++)
    {
        cosVal = pCoef[2 * ia];
        sinVal = pCoef[2 * ia + 1];
        ia++;

        l = i + n2;
        xt = (pSrc[2 * i] >> 2) - (pSrc[2 * l] >> 2);
        pSrc[2 * i] = (pSrc[2 * i] >> 2) + (pSrc[2 * l] >> 2);

        yt = (pSrc[2 * i + 1] >> 2) - (pSrc[2 * l + 1] >> 2);
        pSrc[2 * i + 1] = (pSrc[2 * l + 1] >> 2) + (pSrc[2 * i + 1] >> 2);

        mult_32x32_keep32_R(p0, xt, cosVal);
        mult_32x32_keep32_R(p1, yt, cosVal);
        multAcc_32x32_keep32_R(p0, yt, sinVal);
        multSub_32x32_keep32_R(p1, xt, sinVal);

        pSrc[2u * l] = p0 << 1;
        pSrc[2u * l + 1u] = p1 << 1;

    }

    // first col
    arm_radix4_butterfly_q31( pSrc, n2, (q31_t *)pCoef, 2u);
    // second col
    arm_radix4_butterfly_q31( pSrc + fftLen, n2, (q31_t *)pCoef, 2u);

    for (i = 0; i < fftLen >> 1; i++)
    {
        p0 = pSrc[4 * i + 0];
        p1 = pSrc[4 * i + 1];
        xt = pSrc[4 * i + 2];
        yt = pSrc[4 * i + 3];

        p0 <<= 1;
        p1 <<= 1;
        xt <<= 1;
        yt <<= 1;

        pSrc[4 * i + 0] = p0;
        pSrc[4 * i + 1] = p1;
        pSrc[4 * i + 2] = xt;
        pSrc[4 * i + 3] = yt;
    }

}

void arm_cfft_radix4by2_inverse_q31(
    q31_t *pSrc,
    uint32_t fftLen,
    const q31_t *pCoef)
{
    uint32_t i, l;
    uint32_t n2, ia;
    q31_t xt, yt, cosVal, sinVal;
    q31_t p0, p1;

    n2 = fftLen >> 1;
    ia = 0;
    for (i = 0; i < n2; i++)
    {
        cosVal = pCoef[2 * ia];
        sinVal = pCoef[2 * ia + 1];
        ia++;

        l = i + n2;
        xt = (pSrc[2 * i] >> 2) - (pSrc[2 * l] >> 2);
        pSrc[2 * i] = (pSrc[2 * i] >> 2) + (pSrc[2 * l] >> 2);

        yt = (pSrc[2 * i + 1] >> 2) - (pSrc[2 * l + 1] >> 2);
        pSrc[2 * i + 1] = (pSrc[2 * l + 1] >> 2) + (pSrc[2 * i + 1] >> 2);

        mult_32x32_keep32_R(p0, xt, cosVal);
        mult_32x32_keep32_R(p1, yt, cosVal);
        multSub_32x32_keep32_R(p0, yt, sinVal);
        multAcc_32x32_keep32_R(p1, xt, sinVal);

        pSrc[2u * l] = p0 << 1;
        pSrc[2u * l + 1u] = p1 << 1;

    }

    // first col
    arm_radix4_butterfly_inverse_q31( pSrc, n2, (q31_t *)pCoef, 2u);
    // second col
    arm_radix4_butterfly_inverse_q31( pSrc + fftLen, n2, (q31_t *)pCoef, 2u);

    for (i = 0; i < fftLen >> 1; i++)
    {
        p0 = pSrc[4 * i + 0];
        p1 = pSrc[4 * i + 1];
        xt = pSrc[4 * i + 2];
        yt = pSrc[4 * i + 3];

        p0 <<= 1;
        p1 <<= 1;
        xt <<= 1;
        yt <<= 1;

        pSrc[4 * i + 0] = p0;
        pSrc[4 * i + 1] = p1;
        pSrc[4 * i + 2] = xt;
        pSrc[4 * i + 3] = yt;
    }
}

